The SMS Generator is a tool that allows students create a text message conversation between two people. I would use this tool in my English classes, during our literature units. Students can create conversations between characters, or between themselves and a character.
Voki is a tool that allows you to make a character talk. Users are able to create their own speeches for the character. This would be a great tool to use in both my math and English classes. In math class, I could have my students create a Voki to teach someone how to solve a certain type of problem.